Tag: Heat Transfer guidelines of Garments Manufacturing

Heat Transfer Operation
and Guidelines of Garments Manufacturing

Heat Seal Label: In garments manufacturing it’s called heat seal or heat transfer label which shows the company’s brand logo or other important messages. Heat seal label is very attractive to a customer so its quality should be first class and label attaching process is very sensitive. Label attach by pressure and heat that’s why it’s called heat transfer Label. In this article we will have detail discussion of Heat Transfer Operation and Guidelines of Garments Manufacturing.

Head
plate should be made of metal and Teflon coated to prevent soiling which could
contaminate the garments.

Base
plate must be made of silicon rubber or can be a fleece platform with
sufficient resilience to ensure close alignment with the upper heat press
platen. A fleece platform is recommended to use for the application of 3
dimensional heat transfer.

Platen
size should be at least 38 x 38 cm (15” x 15 “)

Plate
should be bigger than artwork.

Machine Height

Heat
transfer presses must be adjusted in a way that the operator has an
unobstructed view of the application area and is able to quickly identify any
problems.

Calibration of the Heat Transfer
Presses

H/T machine
should be calibrated daily to obtain a reliable and consistent result.

Required Tools Calibration of the
Heat Transfer Presses

Thermocouple or Thermo-labels

A Stop watch, Cleaning cloth, Machine Calibration Check Log

Machine Inspection

Head
and base plates of the heat transfer presses must be inspected for damage &
contamination. The plates must be clean and smooth without any adhesive
residue.

The
rubber base plates must be replaced, if it becomes distorted or hard.

Heat Sealing Machine Calibration
Check

Temperature,
Pressure and Time must be controlled and documented at a style level.

Temperature Check

To ensure
that the heat is allocated evenly across the platen and the temperature meter
(input temperature) matches the actual output temperature.

Start the machine and set the Temperature at 160 C, time 30 seconds and Pressure at 3 bar (45 PSI).

Place 5 Thermo-label set onto the base plate at the upper right, upper left, center, lower left and lower right position.

Swing the machine onto the position and run a press cycle with time of 30 seconds.

Remove the thermos-labels and review the darkened labels. Each darkened label represents a temperature that the equipment successfully reached.

Record the highest temperature reached for each location in the Heat Transfer Machine Calibration Check Log.

Instead of Thermo-labels, also a Thermocouple can be used to check the temperature.

A temperature tolerance of +/- 3 C is acceptable.

Contact the manufacturer for service if the equipment failed.

The use of a
digital temperature control is recommended to have an accurate temperature
information.

Pressure Balance Check

Test the
pressure between the upper and lower plate of the machine

Place
4 paper strips in same size on top of the base plate.

Activate
the machine to press the strips in between

Pull
the strips sideward with equivalent strength to feel the pressure.

In
case the pressure is uneven and strip pulled out, replace the whole silicon or
fleece platform or contact the manufacturer for checking.

The use of pneumatic
pressure is recommended to give a stable pressure.

Time Check

Set
the time of the machine to 30 seconds.

Put
the machine into position and press the start buttons & at the same time
start the stopwatch.

Measure
the time for the machine to carry out its cycle.

Record
the time in the calibration log and repeat until 5 cycles are completed.

Calculate
the average and compare log and compare the value to 30 seconds.

The
result should be +/- 0.5 seconds

If
outside this, contact the press manufacturer to reset the timer.

Record
the result in the Heat Transfer Calibration Check Log.

Time should
be calculated from the moment of contact between application head and heat
transfer.

Before any
operation refer to the heat transfer specifications from the supplier for
detailed application directions i.e. Time & Peel Instruction.

Make
sure that the machine has been calibrated before operation start.

Make
sure that the press platens are clean and free of any residue.

Start
the machine and set the temperature, pressure and time which are given by the
Heat Seal Transfer supplier application instructions. Allow correct time to
heat for newly start machine (morning and after breaks) before bulk production.

Put
the fabric panel over the base plate and place the heat transfer on the desired
location of the panel.

Make
sure that the fabric is smooth but not stretched tight.

Cover
a release paper on top of the fabric to avoid direct contact of the heat platen
with the fabric.

Activate
the press for one application cycle.

Some
special heat transfer qualities require a second heat pressing process on the
reverse side of the fabric. It is crucial to follow exactly the Heat Transfer
application instructions.

Remove
the fabric panel from the press and peel off the transparent backing paper as
per the application instructions either immediately while the transfer is still
hot or after cooling down.

Do
not stack panels until they have fully cooled.

Heat
Transfer machines must be checked every 2 hours during print application for
correct temperature, pressure and time.

Different
positions of the application platform, middle and outer edges should be
checked. Result must be documented at the Heat Transfer Application Check Log
and displayed at the machine.

Heat Transfer Quality Tests Prior to Production

Development Stage

All heat
transfer must be applied and tested on the intended bulk quality. This is to
ensure that the die migration, strength of attachment, color change/staining, damage/defects
and elasticity can be correctly assessing.

Sample Wash Test

Heat
transfer prints on samples must be applied according to the given application
instruction. Garment supplier must wash one sample at 40 C (Tumble Dry) to
determine problems at early stage. In case the heat transfer on the washed
garments shows ay negative appearance regarding color change or peel off,
garment supplier must inform heat transfer supplier and immediately discuss
further actions. The washed sample and wash test report must be archived by the
garment maker and keep for two seasons.

Heat Transfer Supplier Quality Test on Bulk Fabric

As soon as
the bulk fabric is available in the factory, garment supplier must send one
yard in darkest fabric color to the Heat Seal Transfer supplier for testing.

In case
fabrics are delayed, it is the responsibility of the garment maker to inform
the Heat Transfer supplier about the fabric code. In that case, the Heat
Transfer supplier can arrange the fabric directly from the fabric supplier.

The heat transfer supplier must test on the bulk fabric to identify and confirm the correct application process. Once the washing tests, colour fastness, and migration tests are PASSED, the heat transfer supplier must inform the garment maker supplier about the recommended application instruction.

Garment Supplier Quality test on Bulk Fabric

As soon as the garment supplier receives the confirmed application instruction from the Heat Transfer supplier, garment supplier must apply for the transfer on the bulk fabric in all colorways and arrange the following quality checks.

The tests
must be done on all heat transfer machines which are intended to be used for
production. All quality tests must be done after samples are cooled down for at
least 24 hours after application. The washing test can be done by the garment
supplier if accredited by Buyer. Test can be done by a laboratory which is
accredited by Buyer.

In case one
of the above test fails, garment supplier must notify immediately the
respective heat transfer supplier for further action to solve the problem. The
original pass test reports and print swatches (before and after washing) must be available as reference
sample at the respective machine print production.

Heat Transfer Quality Check on Printed Panels

100% quality
check of the printed panels.

Before
quality check, allow printed panels to cool down.

Check
all edges and corners for solid bond

Check
melting of glue

Check
for color staining / bleeding on the test samples.

Report
any print defects like cracking or peeling-off problems.

Check
bulk output every 2 hours

If you have any confusion then please let us know, we will discuss further.